| Using electrophysiological and behavioral measures, this study investigated possible motor programming and learning deficits in Parkinson's disease (PD) relative to healthy age-matched controls. Participants performed a speeded reaction time task with response requirements varying in complexity. Each trial began with a warning signal indicating the hand of response followed by a Go or NoGo signal. Responses included a sequence of three keypresses (e.g., middle, index, ring finger) contrasted with a single keypress response. Lateralized readiness potentials (LRP) and false alarm rates both indicated motor programming deficits in PD patients relative to controls. This occurred despite the fact that PD patients demonstrated normal slowing of reaction time (RT) during sequential responses. RT and movement time across trials suggested that PD patients also have some degree of motor learning impairment. Electrophysiological measures were sensitive to learning effects, however, these measures did not differentiate the two groups. |
